Pet battle XP sometimes doesn't display but you still get it

[Polynices]

Anyone else notice this one? Usually when I win a pet battle the experience award and any leveling up is shown in my chat window. Occasionally it doesn't show up at all, but my pets still get experience and might level up, but I only see it by opening the pet window.

Obviously, this isn't a huge deal, I'm still getting the XP. But I can't figure out if anything in particular causes it (I mostly fight trainers, not sure if I've seen it against random wild pets or in PvP). But I thought I'd see what other people have experienced.

[Catalytic]

I have been noticing it, as well, and it has happened in the wild and with tamers. Someone else mentioned in a post here somewhere that maybe it happened when we were supposed to get a battle-stone and didn't? (Vague memory here, sorry)

[Poofah]

Someone else mentioned in a post here somewhere that maybe it happened when we were supposed to get a battle-stone and didn't? (Vague memory here, sorry)

I think that was me, and I think I'm most likely wrong. I've seen some anecdotes saying that certain abilities tend to skip the ending animations and XP display, in particular Devour. I'm leaning toward that explanation.

[Ryna]

I had a few of these happen yesterday directly after the opposing pets decided to fight underground, which made my pets take baby steps (while looking like they were running) to hit. After the last hp was taken from the opposing team, the battle would end abruptly as if I were pulled out by combat. I didn't look to see if I got exp, though.

[Delinda]

I didn't get XP today twice. I checked the battle log and the level of the pet didn't change. What the hell? The pets were not lvl 25